HighlightsThe effects of the carbon/nitrogen ratios of 40, 90, 140, and 190 on hydrogen production are evaluated by varying the nitrogen source in an upflow fixed-bed anaerobic reactor.An optimal C/N ratio of 137 to produce 3.5 mol H2 mol−1 sucrose is estimated by a mathematical approximation.Continuous decreases in the specific organic loading rate as a function of time seemed to be responsible for the instability of the system.A microbial biology analysis identified hydrogen-producing and -consuming microorganisms from natural inoculum.

Endophytic fungi are microorganisms that live within plant tissues without causing disease during part of their life cycle. With the isolation and identification of these fungi, new species are being discovered, and ecological relationships with their hosts have also been studied. In Glycine max, limited studies have investigated the isolation and distribution of endophytic fungi throughout leaves and roots. The distribution of these fungi in various plant organs differs in diversity and abundance, even when analyzed using molecular techniques that can evaluate fungal communities in different parts of the plants, such as denaturing gradient gel electrophoresis (DGGE). Our results show there is greater species richness of culturable endophytic filamentous fungi in the leaves G. max as compared to roots. Additionally, the leaves had high values for diversity indices, i.e. Simpsons, Shannon and Equitability. Conversely, dominance index was higher in roots as compared to leaves. The fungi Ampelomyces sp., Cladosporium cladosporioides, Colletotrichum gloeosporioides, Diaporthe helianthi, Guignardia mangiferae and Phoma sp. were more frequently isolated from the leaves, whereas the fungi Fusarium oxysporum, Fusarium solani and Fusarium sp. were prevalent in the roots. However, by evaluating the two communities by DGGE, we concluded that the species richness was higher in the roots than in the leaves. UPGMA analysis showed consistent clustering of isolates; however, the fungus Leptospora rubella, which belongs to the order Dothideales, was grouped among species of the order Pleosporales. The presence of endophytic Fusarium species in G. max roots is unsurprising, since Fusarium spp. isolates have been previously described as endophyte in other reports. However, it remains to be determined whether the G. max Fusarium endophytes are latent pathogens or non-pathogenic forms that benefit the plant. This study provides a broader knowledge of the distribution of the fungal community in G. max leaves and roots, and identifies the genetic relationships among the isolated species.

Dengue is a neglected disease responsible for 22,000 deaths each year in areas where it is endemic. To date, there is no clinically approved dengue vaccine or antiviral for human beings, even though there have been great efforts to accomplish these goals. Several approaches have been used in the search for dengue antivirals such as screening of compounds against dengue virus enzymes and structure-based computational discovery. During the last decades, researchers have turned their attention to nature, trying to identify compounds that can be used as dengue antivirals. Nature represents a vast reservoir of substances that can be explored with the aim of discovering new leads that can be either used directly as pharmaceuticals or can serve as lead structures that can be optimized towards the development of new antiviral agents against dengue. In this review we describe an assortment of natural products that have been reported as possessing dengue antiviral activity. The natural products are organized into classes of substances. When appropriate, structure-activity relationships are outlined. The biological assays used to assess antiviral activity are briefly described.

The composition and diversity of fungal communities associated with three endangered orchid species, Hadrolaelia jongheana, Hoffmannseggella caulescens, and Hoffmannseggella cinnabarina, found in different vegetation formations of the Atlantic Forest were determined by constructing clone libraries and by applying diversity and richness indices. Our results demonstrated the presence of Basidiomycetes. Sebacinales (81.61%) and Cantharellales (12.10%) were the dominant orders and are potential candidates for orchid mycorrhizal fungi. The Ascomycetes identified included the Helotiales (29.31%), Capnodiales (18.10%), and Sordariales (10.34%), among others. These orders may represent potentially endophytic fungi. A Shannon-Wiener diversity index (H') analysis showed a relatively high fungal community diversity associated with these tropical orchids. This diversity may offer greater flexibility in terms of the adaptation of the plants to changing environmental conditions and the potential facilitation of reintroduction programs. The Simpson diversity index values showed that all of the libraries included dominant species, and a LIBSHUFF analysis showed that the fungal communities were structurally different from each other, suggesting an influence of local factors on this diversity. This study offers important information for the development of conservation strategies for threatened and endemic species of Brazilian flora in an important and threatened hotspot.

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